There are different types of surgical interventions in which the operating surgeon has to work on moving organs of the human body. This is the case, for example, in a coronary artery bypass graft (CABG) surgery on the beating heart. In such bypass graft surgery, a portion of a contracted coronary artery has to be bypassed using a graft vessel, wherein the vessel is sewed to the artery at two positions. Therefore, this operation is frequently carried out using a heart-lung machine under cardioplegla. As soon as the intervention is completed, the heart is made to beat again. This operation can also be carried out without a heart-lung machine while the heart is beating. As a matter of course, an operation on a beating heart is by far more difficult for the operating surgeon to perform than an operation on a non-beating heart. Therefore devices for stabilizing and immobilizing a part of the heart are required.
One type of stabilizing device is based on the vacuum principle. It includes elements which are attached to a part of the heart and fixed in place by means of a vacuum. The entire device comprises a stationary part which is usually fixed to a rib spreader, a flexible arm consisting of a plurality of individual elements, an actuating element by which said arm is tightened, and one or more vacuum elements to which a vacuum hose is connected. In said arm, a pull rope is provided which is mechanically braced by means of the actuating element. The pull rope is tightened via a worm or an eccentric gear. Said devices are known, for example, from the documents U.S. Pat. No. 6,866,628 B2, U.S. Pat. No. 7,311,664 B2, U.S. Pat. No. 7,399,272 B2, U.S. Pat. No. 7,476,196 B2 or U.S. Pat. No. 7,479,104 B2.
The second type of stabilizing device functioning without a vacuum is very similar. In this case, the technology consists of the same components except for the vacuum elements. Instead of vacuum elements, in this case there are inoperable, inactive elements, such as fork-like stabilizing elements, that are pressed onto part of the heart so as to stabilize that part of the heart purely mechanically. This technology is described, for instance, in U.S. Pat. No. 6,581,889 B2.
It is a drawback of the previous solutions that with all common devices the user has to work with both hands for this type of procedure. At the proximal end, the user arrests the flexible arm by means of the operating element provided for this purpose, while he/she guides the distal end and presses it onto the tissue. This operating step is further complicated by the flexible link arm having at its proximal end a pivot axis by which it can be pivoted in the horizontal plane toward the stationary part attached to the spreader. This pivot axis in many cases is locked simultaneously with the arm by means of the same pull rope. In extreme cases, the user may require an assistant, for example for retaining the pivot axis at the desired position during the locking operation.
Moreover, with these devices, it is frequently not defined how strongly the pull rope is tightened. Different users will operate the actuating element, which frequently is a screw mechanism, differently depending on their own sense of feel and strength, and thus will generate both different tensile forces and different rigidities of the link arm.
Another drawback resides in the high cost for using such a device. Due to the fact that the individual arm segments and the pull rope consisting of plural single strands to ensure flexibility are difficult to clean in an efficient manner, the entire instrument is not re-usable and is used only once.